As the conventional chemical heat storage devices, for example, a chemical heat storage device described in Patent Literature 1 is known. The chemical heat storage device described in Patent Literature 1 includes a first container disposed upstream of a catalyst body in a gas passage pipe and accommodating an adsorbent which adsorbs/desorbs water as an adsorbed medium to generate/absorb heat, a second container disposed externally to the gas passage pipe and accommodating the adsorbed medium, a communicating pipe communicating the first container with the second container, and an on-off valve disposed halfway of the communicating pipe. If an ignition key is turned on (engine is started), and the on-off valve is opened, the catalyst body is heated and activated by the heat generated accompanying adsorption by the adsorbent. If the catalyst body is sufficiently activated, the adsorbent receiving the heat of the catalyst body is desorbed and be regenerated.